53 continued 612906 0181 437915 487 1 2 0085 from

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Unformatted text preview: 3600)(90.6) = 5.9(3.14)(0.181) 1/ 2 = 3.6 ft. (a) For liquid holdup estimates, assume the column operates in the preloading region. Therefore, the holdup is independent of the gas rate. Follow Example 6.12. Pertinent packing characteristics from Table 6.8 are a = 92.3 m2/m3 = 28.1 ft2/ft3, = 0.977, and Ch = 0.876 Use Eqs. (6-97) to (6-101), which requires calculating the liquid Reynolds and Froude numbers. Liquid holdup based on conditions at the top of the column. By the continuity equation, superficial liquid velocity is, uL = LML /LS = (437/3600)(79.9)/ [50.6(3.14)(3.8)2/4] =0.0168 ft/s 0.0168 50.6 u From Eq. (6-98), N Re L = L L = = 145 L a (0.31)(0.000672)281 . u 2 a ( 0.0168 ) 28.1 From Eq. (6-99), N FrL = L = = 2.46 10 -4 g 32.2 Since NRe > 5, use Eq. (6-101), 2 0. 0 ah / a = 0.85Ch N Re25 N Fr.1 = 0.85(0.876)(145) 0.25 (2.46 10-4 ) 0.1 = 112 . L L Exercise 7.53 (continued) Analysis: (a) top of the column (continued) From Eq. (6-97), the fractional liquid holdup is, hL = 12 N FrL N...
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This note was uploaded on 09/08/2008 for the course CHE 244 taught by Professor Selebi during the Spring '06 term at Lehigh University .

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